Tildia Williams & Henning, 2023

Williams, Mark C. & Henning, Graham A., 2023, Taxonomic revision of the tribe Acraeini Boisduval, 1833 (Papilionoidea: Nymphalidae: Heliconiinae), Metamorphosis 34 (1), pp. 35-49 : 41-42

Genus Tildia Williams & Henning, 2023 gen. nov.

urn:lsid:zoobank.org:act:1F4BB732-A5DD-4F70-AB86-7F8B395C856A

Type species Papilio zetes Linnaeus, 1758

This is a purely Afrotropical genus of 13 fairly large to large species. The lineage arose ~ 17 Mya.

Body: Head large, broad and hairy. Antennae shorter than half length of forewing, averaging 42.5% (37-46%) of forewing for both sexes. Palpi 1 st joint twice as long as broad, 2 nd joint three times longer than first joint and terminal joint minute, oval. All joints hairy. Thorax short, compressed laterally, hairy and scaly. Abdomen long, extending beyond outer edge of hindwings, laterally compressed, broader distally. Legs: Anterior legs slender and less than half length of pterothoracic legs; tarsi of male single joint without spines, female tarsi five jointed with spines on each except last, no terminal spines. Pterothoracic legs, robust, external claw of male furrowed on inner surface, terminal claws asymmetrical. Wing venation: Radial veins of forewing not stalked; R 1 branching off from cell rather than stalked. Cell of hind wing more than half of total wing length. Markings: Similar in placement to Acraea but with marginal markings or spots on forewing upper side in both species groups. Male genitalia: Uncus beak-shaped and elongate, as long, or longer, than tegumen, arched, acute at tip; aedeagus thin, needle like, curved; sclerotized and modified 8th tergite or sternite not present; valves very elongated, not triangulate basally and have inward projections, not fused basally, more than twice length of uncus; juxta extremely narrow, elongated and strongly sclerotized; vinculum broad and almost filling the saccus. Female genitalia: Anal lobes short, produced ventrad, posterior apophyses longer than lobes and supporting sclerites combined. Sterigma usually taking the form of a large U-shaped plate; ostium anteriorly placed; ductus short and sclerotized; bursa elongate or spherical; two signa, very small or absent. Sphragis present.

Early stages: Egg squat, ovoid, almost as broad as high; laid in small batches. The larvae are gregarious. Pupa white to creamy, with black lines marking the nervules on the wing covers. Host plant genera: Adenia (6 records), Passiflora (2 records) and Basananthe (2 records). The following plant genera have been recorded only for T. zetes : Vitis , Barteria, Deidama , Hydnocarpus , Phyllobotryum , Smeathmannia and Tacsonia . Host plant families: Passifloraceae (7 records), Flacourtiaceae (1 record), Vitiaceae (1 record). Habitats (biomes): A predominantly woodland and savanna genus, with a single species in the Namib desert. Woodland (5 spp.), savanna (4 spp.); coastal forest (2 spp.); Namib Desert ( T. hypoleuca ). Geographical range: Kenya and Tanzania have the most species (7 each), with six species in southern DRC and five species in Angola, Zambia, Mozambique, South Africa and Namibia. There are four species in Malawi, Zimbabwe, Botswana and Ethiopia, and three in Southern Sudan, Uganda, Somalia and Swaziland. One species ( T. zetes ) is widespread in the Afrotropical Region and there is a single species in Madagascar ( T. turna ).

Diagnosis

Facies: The genus Tildia can be distinguished from Acraea by the presence of marginal spots on the forewing upper side in species from each species group. The genus Cethosia has marginal spots on the forewing upperside as has anacreon , the earliest offshoot of Telchinia (Carvalho et. al., 2021) and as do other tribes in the Subfamily Heliconiinae . Some species of Tildia have normal markings entirely absent on the upper side.

Genitalia: The male genitalia in Tildia are fairly simple in comparison to the adaptations in Acraea genitalia. In Acraea horta species-group the 8 th sternite is modified to form a protective plate called a velum, in the machequena species-group the valves are strongly incurved forming a claw, in the satis species-group the 8 th tergite is produced into a pseudouncus with the rest reduced in size, in the admatha species-group the juxta is articulated by a transtilla and connected by an elongate sclerite, in the quirina species-group the uncus is divided into two hooks as large as the valves. In comparison the male genitalia of Tildia are simple with the valves greatly elongated and not subtriangular and the juxta narrow, elongated and strongly sclerotized. The vinculum is also largely enclosed within the saccus. In the female genitalia the ostium is anteriorly placed as compared to Acraea which are central or posteriorly placed in the species examined.

Species list